Restoration mechanisms in highly deformed Cu-based conductor wires

Conductor wires used in pulsed magnets are traditionally fabricated by wire drawing. The strength of the conductors is influenced by the microstructure, which is partly dependent on the restoration mechanisms occurring during processing. This study provides an insight into the types of restoration mechanisms occurring during wire drawing of OFHC copper. The effects of the restoration mechanisms on the mechanical and electrical properties of the material were determined. Tensile tests revealed the existence of steady state stress followed by strength softening at large processing strain. Optical and orientation imaging microscopy (OIM) showed that the strength softening coincided with the onset of recrystallization in the material. Although restoration mechanisms of recovery and recrystallization played some role in the strengthening they had little or no effect on the resistivity of the material.